object-file-convert: convert tag objects when writing
When writing a tag object in a repository with both SHA-1 and SHA-256,
we'll need to convert our commit objects so that we can write the hash
values for both into the repository. To do so, let's add a function to
convert tag objects.
Note that signatures for tag objects in the current algorithm trail the
message, and those for the alternate algorithm are in headers.
Therefore, we parse the tag object for both a trailing signature and a
header and then, when writing the other format, swap the two around.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>